Abundant copy-number loss of CYCLOPS and STOP genes in gastric adenocarcinoma

Background Gastric cancer, a leading cause of cancer death worldwide, has been little studied compared with other cancers that impose similar health burdens. Our goal is to assess genomic copy-number loss and the possible functional consequences and therapeutic implications thereof across a large series of gastric adenocarcinomas. Methods We used high-density single-nucleotide polymorphism microarrays to determine patterns of copy-number loss and allelic imbalance in 74 gastric adenocarcinomas. We investigated whether suppressor of tumorigenesis and/or proliferation (STOP) genes are associated with genomic copy-number loss. We also analyzed the extent to which copy-number loss affects Copy-number alterations Yielding Cancer Liabilities Owing to Partial losS (CYCLOPS) genes–genes that may be attractive targets for therapeutic inhibition when partially deleted. Results The proportion of the genome subject to copy-number loss varies considerably from tumor to tumor, with a median of 5.5 %, and a mean of 12 % (range 0–58.5 %). On average, 91 STOP genes were subject to copy-number loss per tumor (median 35, range 0–452), and STOP genes tended to have lower copy-number compared with the rest of the genes. Furthermore, on average, 1.6 CYCLOPS genes per tumor were both subject to copy-number loss and downregulated, and 51.4 % of the tumors had at least one such gene. Conclusions The enrichment of STOP genes in regions of copy-number loss indicates that their deletion may contribute to gastric carcinogenesis. Furthermore, the presence of several deleted and downregulated CYCLOPS genes in some tumors suggests potential therapeutic targets in these tumors.Singapore. Ministry of Health (Duke-NUS Signature Research Programs)Singapore. Agency for Science, Technology and ResearchSingapore-MIT Allianc

Chemokine-driven lymphocyte infiltration: an early intratumoural event determining long-term survival in resectable hepatocellular carcinoma

Objective Hepatocellular carcinoma (HCC) is a heterogeneous disease with poor prognosis and limited methods for predicting patient survival. The nature of the immune cells that infiltrate tumours is known to impact clinical outcome. However, the molecular events that regulate this infiltration require further understanding. Here the ability of immune genes expressed in the tumour microenvironment to predict disease progression was investigated.MethodsUsing quantitative PCR, the expression of 14 immune genes in resected tumour tissues from 57 Singaporean patients was analysed. The nearest-template prediction method was used to derive and test a prognostic signature from this training cohort. The signature was then validated in an independent cohort of 98 patients from Hong Kong and Zurich. Intratumoural components expressing these critical immune genes were identified by in situ labelling. Regulation of these genes was analysed in vitro using the HCC cell line SNU-182.ResultsThe identified 14 immune-gene signature predicts patient survival in both the training cohort (p=0.0004 and HR=5.2) and the validation cohort (p=0.0051 and HR=2.5) irrespective of patient ethnicity and disease aetiology. Importantly, it predicts the survival of patients with early disease (stages I and II), for whom classical clinical parameters provide limited information. The lack of predictive power in late disease stages III and IV emphasises that a protective immune microenvironment has to be established early in order to impact disease progression significantly. This signature includes the chemokine genes CXCL10, CCL5 and CCL2, whose expression correlates with markers of T helper 1 (Th1), CD8(+) T and natural killer (NK) cells. Inflammatory cytokines (tumour necrosis factor α, interferon γ) and Toll-like receptor 3 ligands stimulate intratumoural production of these chemokines which drive tumour infiltration by T and NK cells, leading to enhanced cancer cell death.ConclusionA 14 immune-gene signature, which identifies molecular cues driving tumour infiltration by lymphocytes, accurately predicts survival of patients with HCC especially in early disease

Organ and Tissue Transplantation

ANNALS ACADEMY OF MEDICINE SINGAPORE384289-29

COVID-19 and the impact on surgical training and education in Singapore

10.1016/j.heliyon.2022.e08731HELIYON8

MiR-214 Targets β-Catenin Pathway to Suppress Invasion, Stem-Like Traits and Recurrence of Human Hepatocellular Carcinoma

10.1371/journal.pone.0044206PLoS ONE79

<i>EZH2</i> and <i>CTNNB1</i> are downstream targets of miR-214 and both are upregulated in human HCC tissue samples.

<p>(A) Effect of miR-214 on <i>EZH2</i> and <i>CTNNB1</i> expression, as shown by a luciferase reporter assay. The data were normalized by the ratio of Firefly and Renilla luciferase activities measured at 48 h post-transfection. The bar graph showed the mean ± SD in three independent transfection experiments. *<i>P</i><0.05. (B) Western blotting analysis of EZH2, β-catenin, and E-cadherin expression in P-miR-control- and P-miR-214-transfected SK-HEP-1 cells. (C-E) Validation of the expression of <i>EZH2</i> (C), <i>CTNNB1</i> (D) and CDH1 (E) in 20 paired human HCC tissue samples and 10 samples of histologically normal liver tissues were validated by qRT-PCR.</p

Roles of <i>EZH2</i>, <i>CTNNB1</i> and <i>CDH1</i> on the growth and invasion of HCC cells.

<p>(A) Silencing of <i>EZH2</i> significantly inhibited the growth and significant decreased the ability of SK-HEP-1 cells to invade. (i) Western blots showing the silencing of <i>EZH2</i> by pLVTHM-shEZH2. (ii) The effect of silencing <i>EZH2</i> on cell growth at different time points. (iii) The inhibitory effect of silencing <i>EZH2</i> on cell invasion. (B) Silencing of <i>CTNNB1</i> significantly inhibited the growth of SK-HEP-1 cells. (i) Western blots showing the reduction of β-catenin after transfection with shRNA-β-catenin. (ii) Effects of silencing β-catenin on cell growth at different time points. (C) Over-expression <i>CDH1</i> significantly inhibited the ability of SK-HEP-1 cells to invade. (i) Western blots showing the overexpression of CDH1 by pcDNA3.1-CDH1 plasmid transfection. (ii) The inhibitory effects of overexpressing <i>CDH1</i> on SK-HEP-1 cell invasion. (D) Western blots showing the silencing of EZH2 significantly decreased the expression of CTNNB1 and induced CDH1 expression.</p